


a creature that splits out of your belly like a parasite

by reincarnivore



Category: Kingdom Hearts (Video Games)
Genre: Biting, Blood licking, Cum Inflation, Dubious Consent, M/M, Rough Sex, ansem is a heartless and i mean like an animal but still sentient, pregnancy scare but not really, vanitas isn't trans but has a coochie so take that as you will
Language: English
Status: Completed
Published: 2020-09-10
Updated: 2020-09-10
Packaged: 2021-03-06 18:00:39
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,974
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26383024
Author URL: https://archiveofourown.org/users/reincarnivore/pseuds/reincarnivore
Summary: vanitas sleeps on a warm beach on mornings he can escape his master. darkness is attracted to its kin- but maybe more than that.
Relationships: Ansem Seeker of Darkness | Xehanort's Heartless/Vanitas
Kudos: 19





	a creature that splits out of your belly like a parasite

Vanitas finds himself straying further and further from the Keyblade Graveyard as his Master becomes more and more occupied with his own scheming. As much as he’ll never betray him, there’s swathes of time between where his Master deigns to torture-, train, him, and after a few slips between the darkness into other worlds and remaining ‘uncaught’, Vanitas makes a habit out of exploring while he waits.

There’s a beach that feels so unusually familiar, but not to ‘him’, or even his other, but like a deja vu from somewhere beyond himself. In the morning, when the light creeps over the horizon, the cool air blows across the sand in a way Vanitas finds alluring, but the inhabitants, generally, do not, so he avoids being accosted as he lays face down in the sand. He arrives early to relax for some time in darkness, sleeping away the pain of existence. No one bothers him. A shiver breaks apart from his shallow form from a night cast in pale clouds and rain, after many nights slept here. He’s so comfortable despite the cold, that when something slowly creeps away from the darkness of the cliffs and lays itself beside him, he barely bats an eyelash. It stinks just like him, that thick acrid scent of darkness, so assumes it to be some unversed, perhaps recently torn from his body, but a shift of well worn fabric catches his ears. As much as Vanitas has an instinct to whip around like a feral cat- the figure now pressed to his side is warm and comforting in its darkness- not ‘warm’ like a temperature, but in feeling. When the sun splits over the horizon, the pressure disappears like it had never been there at all.

The next night he naps here, the weather is nicer, but bruises linger about his body, and he sighs heavily into the dirt. He has no fear of it since the first time it napped with him, so when the unseen shadow crawls out from that cavern, Vanitas hardly shifts. It does, however, earn a tilt of his head when what feels like claws sneak out from beneath it’s clothed form, and itches delicately into the roots of his hair. Vanitas doesn’t dare look at the thing, fearing it will disappear under his discerning golden gaze much like it does from the rays of the sun, but he does deign to speak. “Why.”

A long silence sits as it continues to pet him, but from beneath, an internally dis-used voice rasps softly into his ear. “Why not.”

It pets through him until the dawn breaks, and disappears like it had never been.

It becomes such a habit to come here after beatings, the other shadow hardly waits to visit him. Curled up on his limbs like a cat, Vanitas finally dares to look, feeling comfortable enough if it hides from him, he would hardly care. But, it doesn’t. A brown robed form crawls about, hunched over on all fours, from the secret cavern between the cliffs above him. It pauses momentarily when it notices being watched, but continues with a soft nod of its head beneath a pulled over hood. Impossibly black limbs outstretch from the fabric where it simply seems to form through its imprisoned clothes, claws sinking into the sand with each step, until it gently rests down beside him. Vanitas has seen shadows, and neo-shadows, which is somewhat like this thing seems to be- but never has a heartless appeared to have any form of cognizance, so he’s a mote confused- and interested. Even as he leans down to try to look beneath its hood, nothing but deep-rooted darkness greets him- until two eyes flick open to stare back. He thinks- well, those golden eyes faintly glowing in the darkness, they look quite like _mine_ do- but after a moment he thinks instead, they look quite like _Master Xehanort_ , and his nose wrinkles in distaste. “Are you some thing my Master has sent to haunt me?”

“Not that I am aware of,” it speaks with less of a pause this time, but all the same rasping disuse. It doesn’t not sound like his master, at least, but it’s hard to say if that is because its voice hasn’t changed with time and loneliness. “But I am aware of little,” it mumbles.

Vanitas laughs to that, “You’re a heartless. You should be happy you’re aware of anything at all.’

“‘Happy’,” it repeats with its own laugh, ‘his’ own laugh, Vanitas decides, “A heartless does not feel ‘happy’”

“See, I’d agree with you, but I repeat myself- you’re aware of anything, so you might as well be aware of ‘happy’ or ‘anger’ the same.”

“This is true,” he nods, and then creeps closer, eyes closing and slipping beneath his hood as he presses to Vanitas’ side. In mimicked behavior, Vanitas slowly raises a hand, and sets it over the clothed hood to rub at the perceived back of the shadows neck. He rumbles in content, “ _You’re_ no heartless.”

“Did you think I was?”

“You smell quite like you are. But no, I knew well you were not. In parts, me and you, define as impossibly similar, but in equal faces so intimately unalike.”

Well, now _that_ sounds like Xehanort. As much as Vanitas could squirrel around the subject, he just asks instead, “Are you Xehanort?”

There’s that long pause of thought again, as he adjusts on his arms. “Not like you think.”

“Care to elaborate?”

“We are disparted and thrown across time and space.”

“... So you _were_ Xehanort?” Vanitas hisses, nearly shoving the shadow aside, but it speaks again quicker than he can push.

“As you were once someone else.” 

The parallel catches him off guard, and after thinking it over, Vanitas leans back down. “I guess I won’t be a hypocrite, then,” he mumbles, setting his face down in the sand. He solidifies himself as ‘not Xehanort’ when he props up on his arms, sneaks his face from his hood, and bites at the back of Vanitas’ neck. Not hard, but like an affectionate cat would, snuffling through the short-hairs there. Vanitas speaks, muffled in the sand, “What- is Xehanort’s heartless an _animal_?”

“Are you surprised?” He mumbles into his neck. “Being a heartless is much akin to being a mindless animal. Until I can find purchase in a human form, yes, I will act like a creature more than a man.”

“I guess you look the part,” Vanitas sighs, leaning up enough to see across the ocean. The barest hints of glow are forming at its split between sky and water. “And you’ll disappear like darkness when the run rises.”

“I disappear to where darkness hides,” he replies, pulling away and peering back at the cave he’d so recently creeped from.

“I guess that make sense-” but he’s caught off guard when the shadow bites him again- but napes him like a kitten and starts dragging. Despite a yelp of pain from teeth sinking into his skin, and both arms swinging up to attempt to dislodge himself from the shadow’s grip, it effortlessly totes him across the sand. If he’d not been shit-kicked by his Master earlier today, maybe he could’ve put up more of a fight. Maybe this is why the creature had watched him so diligently over the past few weeks, waiting for that perfect moment of weakness. Vanitas finds himself unable to even work up the effort to complain, and after his initial outburst, lays prone until he’s discarded to somewhere cold and hard. Presumably, in the cave. Now his neck hurts. “ _You_ might be burned by the sun- but despite us being the ‘same’, I’m not scared of it,” he hisses, rubbing the back of his neck and attempting to rise himself, but before he gets far, the shadow knocks him back down and lays across him like a dog with a bone.

“I know well, having watched you sunbath in the morning light more than once,” he retorts, settling down to mumble into his ear. 

“What, are you jealous?”

“Maybe a little.”

“Could’ve just asked if I wanted to come hang out in your big scary cave.”

“You look so content in the sun. Why would you agree to sit in the darkness.”

“Incredibly true, I would’ve said no.”

“So, here we are.”

Again, silence lingers, but now without the soft sounds of waves hitting sand. He can somewhat hear the pulse of it echoing in the distance, but now Vanitas mostly hears his own breath, and an…. Eerie, heartbeat. His own? No… The shadow doesn’t breath, but from beyond the darkness of his heartless form, a weary heart beats painfully beneath his ribs. That acrid scent fills the space so much he can taste it as he breaths, filling his lungs heavy, and again Vanitas feels ‘warm’. Full. It sinks between the cracks in his heart, leaving his mind hazy, and weirdly comfortable. A kind of comfortable he hadn’t been in- in, since he was _this_. And when he thinks about it, it makes sense, since it’s filling between the gaps, but he wonders a bit why it doesn’t just feel _invasive,_ since there’s no part of this shadow he would think it enough ‘him’ to conform to the difference. Like he had said, however, ‘impossibly similar, intimately unalike.’ Is all darkness the same enough? Is all light the same in time? If that was the case, Vanitas wonders, why it’s him that disparts and reforms to unlock the x-blade- but his consciousness blinks out of existence in a moment of warmth.

His attention is aroused again when claws rake over the length of his spine until they tap at that fresh bite at the back of his neck. Vanitas posture stiffens when he expects the nails to dig into the wounds, but they wrap around the back and press down; a cool, wet feeling creeps across the back of his neck and slinks into each cut to lap up the blood. It doesn’t hurt the way he would expect it to, though it isn’t necessarily comfortable, but to the pressure on his back and a habitual lack of fucks to give, Vanitas lays back down, face prone to the ground as the shadow picks at his wounds. When he seems satisfied the bleeding has abated from his licking, his hands wander, sniffing out other places Vanitas’ Master had beaten into him earlier. As much as Vanitas is disgusted being fawned over like this, preened like a kitten, his heart is so comfortably steeped in darkness, and honestly to be given even this broken affection, he has no fight in him to put up. Either way right now he’d be napping, either out in the sand, in the sun, or suppose now, right here. “Do you know me?” Vanitas hums.

“I know you as well as _you_ know you,” the shadow mumbles, picking at the seam of Vanitas’ suit, pulling it away from his skin. It sticks in places where blood pooled and dried beneath it, and he tries not to flinch when it rips away at the shadow’s insistence. Each place the scabbing tears off wells up new patches of blood, and dutifully, the shadow laps up his injuries like fine wine, not hiding the soft noises that escape him pleasurably. Vanitas is content enough to let him have his tastes, since beyond the initial bite to the back of his neck, the shadow doesn’t really hurt him. Between the haze in his mind from the warmth encompassing him, Vanitas doesn’t notice the state of himself until he’s entirely more naked than he’s ever been before. He’s expects to feel the cool morning air on his newly bared skin, but the shadow has his robes, his body draped around him, his heart beating pressed against his back. 

“Lonely, huh,” Vanitas mumbles, weakly reaching an arm back at the shadow.

“Unlike you and your newfound wandering, I am bound to this place,” the shadow rasps in his ear. 

“And why is that?”

“I’m waiting for something fated….”

“What’s fated?”

A pause. “I do not remember,” he sighs, “But I will when it comes.”

“Are you so sure?”

“I can only be sure. We both have no room to doubt.”

“Eh,” Vanitas shrugs as a black hand slinks around his front, running its claws barely across the taut muscled skin of his belly. “I just don’t care about my doubts.”

“Not now, at least,” the shadow laughs, shallow in his chest. He nibbles at the wounded back of Vanitas’ neck, thinking about latching again but resisting the urge with a few more licks. Since he seems to understand the situation he’s in, and loses any squirming he might have had before in the sinking darkness hollowing out his innards, the shadow takes his one wandering hand between the crux of Vanitas’ legs, while the other joins to wrap around his chest. He gives him some room now, and pulls him up on all fours so all his body can be reached. 

He’s not unknown to pleasure, but since it’s only come from his own hand, it’s a sinking, invasive feeling when claws dip between the folds of his sex. The shadow is no stranger to bodies himself, even as barest his memories of being ‘alive’ lay in his mind. Instinct has him dragging the soft pad beneath his claw over a delicate spot that leaves Vanitas with a shaking leg and a soft noise at the back of his throat. It’s a good noise, the shadow thinks, the perfect noise even, so he does it again, two fingers now to pushing against those nerves that has Vanitas creaking in strain beneath him. When he draws a tongue across his neck again, the cries grow sharp, his legs attempting to press together, but the hand rubbing up his sex refuses to be disloged. Forcing itself between pressed thighs, a claw dips its sharp tip into tight folds, and Vanitas shivers at the sensation nearing pain, but the shadow relishes in a wetness that grows with each delicate stroke. 

As much as he could suffice himself with the sensation of rubbing pleasure from the body beneath him, the shadow thinks he’ll get away with just about anything he tries in the moment. Vanitas hums a confused tone when the hand creeps away from his entrance where claws had been threatening to penetrate him, but stiffens when something thick and blunt presses up instead. As much as a finger or two had breached the entrance before, that’s… much, more than that. That competitive drive in him has him bolstered, though, and after that moment's hesitation, Vanitas leans back towards the pressure. A low, rumbling laugh fills the air beside his ear as the shadow leans and bears his weight down again, that arm circled around his chest gripping and pulling back in time. An uncomfortable squeeze between his ribs and between his legs, shallow thrusts leave him heaving in strain when the tip presses and slips away from penetration to rub harshly against that still sensitive stripe of nerves between his legs. Each shock of pleasure catches him more wanton and loose, however, and between strained noises it catches and pushes, breaching thick and prying him apart. A tear nearly falls between squeezed shut eyes, but it’s hardly pain in comparison to what he’d even received hours ago. A different kind of pain, maybe, but not worse, and as the shadow rocks himself deeper and deeper inside, it combines with a harsh pleasantness that has Vanitas hardly able to hold his own weight. His thighs numb from the pressure of holding up his and the shadows weight, alongside the pleasure, and the shadow feels his arms dip. A few more rough thrusts and he’s hilted warmly inside, a rough growl deep in his chest, but before Vanitas can slip down and escape him, even accidentally, the shadow pulls up on his chest until he’s the one above, straddling the shadow’s hips. 

It presses deeper from this angle, and Vanitas can feel himself drool, hands pressing to the black thighs beneath him- his eyes finally open to see the shadow’s legs, away from his robes; he’s an inky black blob in the darkness of the cave, devoid of light entirely, but thick claws outstretch like toes and sink into the ground when he bares up his weigh. Distracted by the movement, Vanitas doesn’t connect the posture change to the incoming fucking, until the equally black claws of the shadow’s hands wrap around his waist and _thrust_. He doesn’t manage to hold his voice for the first few seconds of pure sensation, a strained echoing crying that bounces around them until hands slap across his mouth to muffle, but the shadow doesn’t care either way. The broken cries mix beautifully with the sound of skin on skin, a wet slapping at a pace overwhelming. Though Vanitas takes it like a fresh virgin, over stimulated from _any_ pressure let alone forceful, focused pressure, the shadow chases his own pleasure. He sinks his claws into the skin of Vanitas’ hips when he grabs, pushing out pinpricks of blood neither of them notice until he’s dragging them down into lines- and in that, Vanitas only breaks out into harsh laughter between moans. Any pain that lingers from before or comes on now is drowned out by sensation, sounds and smells of his sex leaking heavy between them. 

It lasts longer than Vanitas can aptly handle, and by the time the shadow’s pace starts to stutter, he’s barely holding up his weight with hands pressed to his thighs. If the shadow had skin under there, he’s surely scratched from Vanitas’ clinging, but there’s no sign of anything between his fingers, and the shadow makes no note of caring. Abruptly, his grip changes, clawing up Vanitas’ front and roughly tugging him back with a squeak. He feels the teeth baring into his neck like pressure and wetness from blood and drool, but he’s too busy feeling the last rough thrusts of an oversized blackness penetrating him so far he feels it well into his belly. It sinks in hilted one last time, and if Vanitas felt warm just sitting in the darkness, he can only comprehend it as _burning_ when it fills into his womb. Does he have a womb? An unsteady hand reaches down to the flat pad of his abdomen as he blankly stares up at the roof- or, _usually_ flat, because he swears he feel that blunt tip of the shadow pressing out his insides, and as he gently rocks his hips to ride out his climax, Vanitas absolutely _bloats_ from whatever the shadow was forcing him to take. It still doesn’t _hurt_ , or doesn’t hurt more than it feels _intensely pleasurable_ , so Vanitas lays there and takes it, feeling out the pressure on his belly until it hits the maximum room he has to fill, and it spills out between the barest gaps of his overused sex and the shadow’s plugging. Apparently that’s unappealing to the shadow, however, and with an unhuman, gurgling growl, he slams up roughly. Again, Vanitas cries out as he’s overwhelmed, and filled, his arms flinging back to grip at the shadow beneath him, but there’s a weird lack of purchase to his body. He swears he feels the shadow’s darkness swell to keep him flooding with itself.

“Wouldn’t it be funny,” the shadow rasps between pleasured rumbles, “if you bloated up with child. You have the parts- but maybe not.” Despite feeling completely full earlier, the shadow finds more of himself to clog any leaks, and Vanitas squirms in the pressure building up inside of him. “Growing something between us two, something twinning us but growing in darkness.” Vanitas eyes dart open, his neck craning to look down at himself, expecting to see some horrible weight between his hips, but he feels much more bloated than he looks. Not to say he isn’t at all- there’s a discernable pouch of fluid pushing up his fingers. The shadows claw slinks down to join Vanitas’ hand pressed to that hollow space, claws barely sinking into his skin. “A dark creature you’d grow _inside_ of you. It would split from your belly like a parasite-” he thrusts once more for good measure, breaking another shrill cry from above before easing his hips down and unleashing a wholly wet sound spilling out beneath him. “It would scream into this world we have given it.”

“What the- the fuck, are you, going on about,” Vanitas barely speaks, moaning when he squeezes and more fluid spills out from inside of him. They both feel the pressure abate with each flex, and the shadow sighs with tapping fingers as Vanitas finds himself mostly flat again.

“Nothing but the wanton wishes of a dead man,” the shadow sighs, laying back down on the ground to catch his breath. Vanitas follows suit, resting his head back down on the shadow’s nearly permeable chest. Or at least, he had expected to get a moment to catch his breath, but those claws find themselves between his legs again, massaging against an over sensitive sex. A leg kicks out in objection, but because it ultimately feels more good that it feels bad, Vanitas doesn’t squirm away- though the shadow’s grip with his other arm about his chest would make it a struggle to do so. Vanitas isn’t sure why he’s torturing him so, since they’d had their fun, but something builds up quickly in his core he’s not familiar with. It catches his breath hard in his throat, a building whine he can’t help, until the pressure spikes like a coil between his legs, punching the air out of him. Again, the shadow latches onto his neck to keep him steady, riding out the given climax he’d apparently never had before, until it genuinely becomes to much, and the boy violently squirms out of his grip. 

He presses his hands firm between his shaking legs, kneeling in a growing puddle of shared fluids. “What the fuck was that,” he stammers, shaking like a leaf as the pressure fades from him, but the exhaustion does not. 

“A present,” the shadow hums, “something you can do to yourself, if you’re eager. Something to deal with pain.”

“I- I’ve… touched, but I…”

“You get bored, thinking there was nothing better. Try to get less bored when exploring, and you’ll learn many, many new things.” He rolls onto his belly, or at least Vanitas thinks he does, because he can fully see him now, and the shadow is very much a blob of darkness. There’s the vague sense of a form in there, where his arms and legs sneak out to claw into the ground, but no light catches his body. At least, where there isn’t a healthy coating of Vanitas’ fluids. He looks down to the shadow’s cum still dripping out of him, and it appears much like his body does. A pure, inky darkness. 

They sit in the silence of Vanitas’ rasping breath and the shadows heartbeat, before a quiet voice breaks, “... I won’t actually, get like… a baby, right.”

There’s the barest tone of confusion to his question before there is another long silence, and the shadow breaks into dark, loud laughter. “No, I would be _quite flabbergasted_ if you’d produced anything in a ‘natural’ way, seeing what you have had created of your wild emotions. Maybe, however, you’ll create something new with this experience- but nothing that will grow within your body. At least, not like that.”

“... good,” he mumbles in reply, rubbing a hand over his belly. He has enough problems in his life- he doesn’t need some unversed eviscerating him to add to the mix.


End file.
